Since when does Twilight count as urban fantasy? That takes place mostly in extremely rural Washington.

My personal favourite in the genre, though I haven't read a lot of it, is probably Neverwhere by Neil Gaiman. I don't think I've ever read a book that takes advantage of its urban setting quite so much as that one. Though Mark Millar's The Good Fairies of New York, which I recently read for the first time, does come close. However, I didn't find the plot as engaging as Gaiman's work.

I like Patricia Briggs, Jennifer Estep, Faith Hunter, Marjorie Liu, C.E. Murphy, Rob Thurman, Karen Marie Moning, Kalayna Price, Kat Richardson, Phaedra Weldon, S.L.Wright.... and several others. I probably read more Urban Fantasy than any other genre now. I used to read mainstream mysteries but they got to be the same thing over and over.